Smart dressing means investing in pieces you can use over and over again.

When Los Angeles mover and shaker Eva Chow caught a glimpse of Alber Elbaz's gold-jeweled bolero from Lanvin's Fall 2008 show, she knew she had to have it. The steep price tag, however, was something she could do without. Truth be told, we all know what it's like: that I-will-die-without-it feeling, increasingly followed by the I-can't-afford-it feeling. But Chow rationalized her potential purchase by ticking off all the fabulous places she could wear it, which she soon did: "It proved to be a great piece that goes with many different looks — I wore it over my long black formal dress for evening, with a blouse and slacks for dinner, and totally dressed down with a white tank and worn jeans for day." And just like that, the lofty $6,000 purchase became a worthwhile investment.

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Moola. Dinero. Bucks. From interest rates to buyouts, there's a never-ending flood of financial jargon in the ether that would leave any fashion lover quaking at the cash register. But there's a new equation for fashion this spring that everyone can compute. It's called CPW (cost per wear), the concept of putting your dollars behind a piece of clothing that you will wear time and time again, making your purchase well worth the investment. Start this season with a new mind-set: Buy less, but buy the best. The former faux pas of repeating an outfit is now shamelessly chic.

Even celebrities have jumped on the bandwagon in a big way. In the past, a starlet wouldn't be caught dead popping up around town wearing the same Chanel suit, Marni print, or Gucci jacket more than once. But repeat-offender actress Katie Holmes carried her Chloé Paraty bag uptown, downtown, and everywhere in between. Natural beauty Jessica Biel picked a showy Louis Vuitton leopard-print scarf to finish off countless ensembles. Best-dressed Jemima Khan reinvented her sleek RM by Roland Mouret frock by selecting different waist cinchers.

CPW diehard Ashley Olsen has been snapped by the paparazzi suctioned into the same leather pencil skirt from the Row on many occasions. Be it dressed down in flats, sexed up in stilettos, or topped off in tights, she's applied a signature styling touch to make her beloved separate look unique every time. The message is clear this season: Multiple manifestations of the same look are no longer taboo. They're right on target.

"It is a return to the pure classics that you can cherish and pull out for seasons to come," emphasizes Barbara Atkin, vice president of fashion direction for department store Holt Renfrew. "Look at someone like Audrey Hepburn and the way she dressed in the 1960s. If we transported her to 2009, she would still look relevant: the perfect little sheath dress, the pearls, the wonderful bag, the beautiful round sunglasses, the ballerinas. It all works. This is a time when, all of a sudden, fast fashion won't be so appealing." It's true: Bid adieu to trendy impulse buys, say hello to investing in the mileage pieces, and haul out the oldies but goodies from yesteryear. Like Hepburn, Chow has perfected the method of selecting these kinds of lasting ensembles. She's looking to have Balenciaga Edition dresses and a white Yves Saint Laurent tux from the archives — die-hard classics, to be sure.

For some, a sturdy standby piece is a little more conspicuous. Manhattan interior designer Celerie Kemble leans on a traditional white fitted blouse as her go-to for almost any outing. "I can wear it to a construction site and get covered in dust or around my children, where it will get doused in baby food," she says. Yet that same Lela Rose-designed ruffled number is also ideal for parties (with the collar up) or business meetings (collar tucked into a blazer). For Kemble, it isn't about running out on every occasion to pick up a cheap, of-the-moment piece; it's more about throwing on a blouse or a skirt that she knows she looks good in — always.

"These investment pieces should be inspiring, so whether you are wearing them for the first time or the hundredth, you still feel amazing," points out Jennifer Mankins, owner of the Brooklyn-based Bird boutique. "I look for special fabrics and prints, a great coat that will go with anything, a stunning dress that works for day or evening, a fabulous bag that complements every outfit." She suggests smart staples from Isabel Marant, whimsical patterned dresses from Thakoon, and designs by young talents like Vena Cava and Alexander Wang.

For evening, Rag & Bone codesigner Marcus Wainwright suggests the trusty LBD: "I like one that can be dressed up or dressed down, something that isn't too completely cocktail but that could be worn with leather leggings underneath." This sort of design is exactly what his edgy yet comfortable brand offers — scores of dark, tailored ensembles that can be mixed and matched.

Atkin adds, "In the luxury market, our customers expect us to come back with the best of the best, which we will continue to do. People are not going to stop shopping, but they will look for quality and won't compromise." This season's shimmery Balenciaga clutch, flesh-toned Lanvin necklace, and loose-fitting boyfriend blazer are all pieces where she's putting her money.

But the list doesn't end there. There is a series of solid CPW pieces that can be trotted out in myriad reincarnations this spring: the traditional Burberry trench coat, a faded pair of dungarees, soft filmy tees, cozy cardigans, and, most of all, a strong statement shoe. Sophie Buhai, one half of the Vena Cava duo, strives to make clothes with this kind of longevity: "If a garment can be worn time and time again and then reinvented 10 years later, you know it's a good design," she says.

So stash away your calculator. It doesn't take a stockbroker, a financial adviser, or any other mathematical whiz to grasp the most economical way to dress this season. The simple solution is to invest in a versatile piece that's worth every penny.